[TowerTalk] Ground radials/elevated radials

[Tom Rauch]

> I do not agree on the elevated radials as being overrated,
for Arizona
> desert anyway.  I had my 40m 4sq installed with 8 buried
radials under each
> element.  The tuning method for the array was to erect all
elements
> identical, observe the frequency where the least amount of
power went into
> the 5th port (the dummy load) in each direction, apply a
little Kentucky
> windage and adjust the vertical elements lengths (all
equal) to the desired
> operating frequency.  I never could observe a frequency
where the wasted
> power was minimum in any direction, and I was never happy
with the array's
> performance.

Everyone pretty much knows eight buried radials can be
somewhat lossy. Dump power, however, has NOTHING to do with
element efficiency. Element efficiency was the concern.  If
you are only going to use four or eight radials and can
stand them hanging in the air, then elevated is definately
the way to go. Just don't pretend it competes with a good
system using an adequate number of radials on the ground. It
doesn't.

> When I moved to the present location I decided to try
again but with
> elevated radials.  I put up 4 tuned radials at 9 feet
elevation under each
> element and the array tuned sharply and works very well.
Good enough that I
> decided to build an 80m 4sq also.  And I am very happy
with it's
> performance.

Being happy is very important, it's really all that matters
for any of us.
But "happy" isn't a unit of field strength and it certainly
is not an efficiency measurement.

In order to measure loss change, we have to measure FS
change. In order to tell if the radial system made a loss
change, we have to ONLY change the radial system and measure
the change in FS with proper protocol. Dump power, SWR, F/B,
and tuning don't tell us a thing about system efficiency. To
do a comparison the systems have to be at the same location.
We have to only change the radial system. We have to measure
F/S, nothing else will work.

> And my RG-213 feed line and RG-11 foam impedance matching
> transformer/phasing lines do not get hot, even running
full power cw during
> a contest (I only run 800 watts on RTTY).

Line heating has nothing to do with ground loss. A feedline
doesn't get any hotter feeding an antenna with 100%
efficiency as it does a dummy load with 0% efficiency.

> I think the important thing here is he wants an effective
antenna and in my
> opinion he will be very, very happy with 4 or even 8
elevated radials under
> each element, provided they are at least 9 feet above
ground.

On the other hand I know people who swore 4 elevated radials
were perfect, until they installed 40-50 radials with no
other changes.

In at least three systems I compared FS of 2, 4, 8, 16, 32,
and 64 radials and compared elevated to ground radials and
while the elevated radials were better than ground radials
when the system was sparse, 3 to 6dB was gained by using
50-60 radials on the ground. WVNJ radio gained 2.5-5.5 dB
when they went from six elevated radials to a conventional
ground system. No other changes, only the radials were
changed.

If anyone wants to give up 3-6dB, lose lightning protection,
have radiating radials, and have the maintanence and
physical clutter problems associated with supporting 4 or 8
wires per vertical in the air, that's OK with me.

I wouldn't be happy with that, but then that's me. Someone
else might not want to bury 25-50 radials, and would prefer
the other system. That's great too.

Let's just not imply the efficiency of four radials 1/25th
of a wavelength above ground is near 90%, like it is with
25-50 wires laying on or in the dirt.

> Further, I will caution him to electrically measure the
1/4 wavelength lines
> rather than use the formulas.  The lines on my 40m 4sq are
stretched taught
> between the phasing box and the element feed points and
according to the
> formula they should have enough slack in them to touch the
ground.

Which is another problem when the system is floated above
ground. We not only have the radials to contend with, we
have to have the feedlines hanging above ground. Some people
certainly don't mind that, but I would.

Since there is no advantage other than perhaps a 50% savings
in labor and wire for the same efficiency, a person just has
to decide what effort he wants to put where. I prefer to
have the system buried, so nothing happens to it. I prefer
to have the lightning protection that buried feedlines and
buried radials provide. I like to have other antennas around
without threading rope through a ceiling of wire, to drive
my truck or tractor through pastures, and to have high
system efficiency. I don't like radiating things with
voltage on them in arm's reach, or near other conductors.

Others might have different priorities. The effort of
burying wire or pinning it to the ground is too great or it
is just mechanically not workable. That's OK too. You do
what you got to do to get on the air.

73 Tom